When Vivian Manifold, Dominus of Imagination, tells a fanciful story ("Evacuate the building! An Ogre is attacking!"),
every mortal in hearing range has their imagination strengthened enough to override their sense of reality;
they are compelled to act as though the story is true, suspending disbelief until he leaves the vicinity.
Which is handy for Vivian, not in the least because occasionally Ogres DO attack, and explanations take valuable time. Also, they're boring.
Afterwards, the mortals tend to dismiss the event as a daydream, drug trip or spontaneous LARPing, which has the added bonus of avoiding Dementia Animus.